Question: Multiply.
Explanation: Let's visualize to help us solve. The array shows ${9}$ rows with ${5}$ squares in each row. $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $1$ $2$ $3$ $4$ $5$ ${9} \times {5} = \underbrace{{5} + {5}+ {5} + {5}+ {5} + {5} + {5}+ {5} + {5}}_{{9}{\text{ fives}}} = 45}$ $45}={9}\times{5}$